Cutting /welding the firewall..... Serious structural degradation.... NOT SAFE!
Something like that can not be "just tac welded into position",
IT would need a complete flange and complete weld, along with keeping the cab structure from sagging after cutting, not to mention hood, fender, glass alignment, and if in a collision you need to keep it from collapsing into an accordion. Way too much time, money, material and Swearing!
All that to find it don't work well, and need to shim the hell out of panels for alignment.
Please wait and find an AC cab for your safety....

I'd say it depends (amount of time saved). If you can get a cab that already has the heater/evaporator box mounted on the engine side + the distribution & ductwork mounted on the interior side, then, yes, you'd save quite a bit!

I got a cab from the JY originally equipped with factory A/C but I stupidly stripped all that stuff off to reduce purchase my costs... wish I hadn't done that.

But I don't know that it would be any easier or faster to swap the entire cab if you're only interested in adding factory AC - besides the dash interior and electrical, there is still the steering column and pedal assembly (easiest is a 2WD manual transmission, hardest will be 4WD automatic), transmission linkages, all the electrical harnesses through the firewall, the fender, cowl and hood mounting, body panel alignment, etc. It's a major change no matter which route you take and, in all cases, I would classify it as a summer project... if you don't give yourself enough time, you're gonna end up with a half-assed, jerry-rigged setup that may or may not be functional that will actually devalue the truck and put it into the POS category IMO.

True, I did a Stripped 4sp cab, to the AC /cruise cab, with auto tranny).

Did the swap and had it functional in 6 hours, I had the take the Stripped cab Standard tranny pedal assembly out of the stripper, and place the whole assembly onto the AC Auto cab. (including the master/slave cylinder).

There were dimples in the Auto-AC cab to locate where to drill for the Clutch mater cylinder. Bolt in the standard 4-sp pedal assembly and it was even plug-and-play for the clutch safety switch and Cruise dump.

Replace the tranny "Hump plate" to the standard tranny one and drive down the road....

Well, sure, it may be "functional" in 6 hours, but not at all finished and complete, especially if you have carpet and trim and power windows and you want all your interior colors to match up and want everything to actually work as designed.

Guys please know I did body & fender work, smashed cars back to full paint & out the door starting back in the mid 70’s. I am a tin knocker body man, you use body fillers as puddy 1/8” max if that!I have built and raced 4x4’s off road, 10 trucks on a moto-x track at once, sand drags & hill climbs.

Also built and auto crossed a 73 Datsun 510 back before lowering and wide wheels where the thing.

I also built from the ground up 70 AMC Javelin for dragracing.

I am also in the middle of a rest-o-mod of a 2nd70 Javelin where I removed the hood frame from the skin of 2 hoods, did Rust Removal UsingElectrolysis then took the best of each to make a good hood for the car. This hood is a 1 year only and if you can find a good one start at $1000 and up! Front fenders were cut buy PO for bigger wheels so I returned them back to stock with welded metal back in. Doors cut the rust out and welded in metal and all treated to stop rust. In the middle of flush mounting front & rear glass welding in metalto fill the gaps – a lot of metal work!

I have also installed custom gauges that look stock if looked at quickly topped off with real silver color carbon fiber over lay again to look stock if looked at quickly. Link to the car so you cansee what I can do. http://cars.grantskingdom.com/index....n-Mark-Donohue

So what I want to do with this truck is not my first time down this path other than it is a Ford and A/C into a non-A/C truck but I am sure when I get stuck I can ask for help and will get it here. Dave----

Well had no work today so not needing to get up at 3am I slept in till 6am and out to the garage by 8am to start pulling the FS truck a part. My plan was to get all of the inside (Seat/dash/wiring/heater box)pulled out and cleaned so I could see what patch panels are needed. Get then nose pulled off and get the cab ready to lift off the frame.Well came close only have the heater box, few other odds n ends and cab bolts to undo for lift off.Cab & engine side wiring Heater box Left side floor rust PO cut it out and had a patch over it.Right side rust Front shot Hope tomorrow to get the heater box pulled the odds n ends removed and cab bolts out so the cab can be lifted off. If I feel up to it start on the bed removal. I want the frame to roll so I can degrease it, prep it and paint it then swap the suspension from the parts truck and duel tanks in to this one. Rust fixed and drop the cab back on. Before I can paint the inside& fire wall I need to see the difference between this non-AC truck and theAC one to see what has to be done to the fire wall to get AC in this truck.I do see the radiator supports are different as someone said but the non-AC one was rusty on the battery side and bent when trying to undo the frame bolt so it is junk.Dave ----

All Internet forums are like this, you are going to get opinions and input from all frames of mind and points of view possible, it's just something you get used to and it will never change.

I under stand the web, it is hard to tell what the others are thinking/saying just from the words they type.

The other is the skill set of the other person. Some can talk the talk but few can do the walk!
Now I am by far an expert but I think I have a pretty good skill set and most of the tools the job needs to have it come out like a pro. Maybe to the point it will be too nice to rive...........not!
Dave ----

Just looked the truck over WOW!
Did answer questions on paint colors for the frame & drive train.

I can see I am going to have fun finding that HVAC control & tank switch panel
If anyone has one (AC/heat/tank switch) they want to part with let me know
as I will need one.
Dave ----

The two junkyards I go to have many of these... the catch is whether it needs to be a 1980 or not. If that is one of the wiring weirdness areas for that year I only know of an F600 off hand that's a 1980. If a 1981-1986 controller will work I can find you one.

The two junkyards I go to have many of these... the catch is whether it needs to be a 1980 or not. If that is one of the wiring weirdness areas for that year I only know of an F600 off hand that's a 1980. If a 1981-1986 controller will work I can find you one.

It has been said the truck I am building is a 1981 by the door sticker but was listed as a 1980 on CL.

But the HVAC & twin tank switch panel is for the 1981
as all this trucks wiring, HVAC and insides are going in the first truck (red paint on sticker) truck.
If you can find at least the HVAC panel but would like HVAC & tank switch panel I would be willing to buy it.
Thanks
Dave ----